Caché (2005)

A married couple is terrorized by a series of videotapes planted on its front porch that may be the direct result from an event from years ago.

A very thorough blog on this movie can be found at Ed Howard's Only the Cinema. I hardly have anything to add, I agree in all major points.

What I did want to add is that this movie very much reminded me of Martin Scorsese's Cape Fear. Both works explore a past and hidden guilt that is revealed by an unexpected, almost super-natural force. And in both cases the major story is that the protagonist takes all the wrong steps when confronted with his own guilt. Scorsese's movie, however, is full of irony, whereas Haneke's approach is multifaceted and open.